CPU Usage 100% with Two Users

[AFGH]

My machine has two users setup and used at the same time. Sometimes when I
switch from one user to the other, the CPU Usage goes to 100%. After much
searching, I realized that the iexplorer.exe on the other (non-active) user
is cycling at 99 - 100%.

This is a very new occurance on a 1 - 2 year old machine. What could be
causing this to happen? Of course, I have run appropriate spyware and
anti-virus checks as well.

Thanks.

 

[AFGH]

Any help? It is actually iexplore.exe that is causing the problem. If I
switch back to the other user and then back again, it sometimes corrects
itself.

Thanks.